In vehicles with bar handle such as a motorcycle (hereinafter, also referred to merely as vehicle), fluid pressure control to reduce, raise or hold the brake fluid pressure by a brake control device for vehicles with bar handle is performed. Examples of the fluid pressure control include ABS (antilock-braking-system) control to suppress a slip of a wheel at the time of braking of the vehicle. In the system disclosed in Japanese Patent No. 2620995, when the inclined attitude angle (bank angle) of a motorcycle is larger than or equal to a predetermined threshold value, holding control to hold the braking pressure of the wheel before the lock pressure of the wheel is reached is performed as the ABS control.
At the time of fluid pressure control, the slip ratio of the wheel is calculated by using the estimated vehicle body speed estimated from the wheel speed, and appropriate processing is performed based on this slip ratio. This estimated vehicle body speed is, for example as disclosed in Japanese Patent No. 2620995, calculated by using the vehicle body deceleration obtained from the time course of the wheel speed when a shift occurs from acceleration to deceleration.
In the vehicles with bar handle, there are cases where when a brake operation is performed at the time of cornering, the estimated vehicle body speed of the vehicle body in the inclined state is calculated by applying a preset constant deceleration similarly to the straightly traveling state. For this reason, in the cornering state, there is a possibility that a difference occurs between the actual vehicle body speed and the estimated vehicle body speed and this affects the execution of the ABS control. That is, in the vehicles with bar handle, it is desired to more accurately calculate the estimated vehicle body speed according to the cornering state.